Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, IPN., Prol. Carpio y Plan de Ayala, Col. Santo Tomás, 11340, Mexico, DF, México.
Biodegradation. 2014 Jun;25(3):405-15. doi: 10.1007/s10532-013-9669-7. Epub 2013 Oct 29.
A microbial community, selected by its ability to degrade triazinic herbicides was acclimatized by successive transfers in batch cultures. Initially, its ability to degrade prometryn, was evaluated using free cells or cells attached to fragments of a porous support. As carbon, nitrogen and sulfur sources, prometryn, (98.8 % purity), or Gesagard, a herbicide formulation containing 44.5 % prometryn and 65.5 % of adjuvants, were used. In batch cultures, a considerable delay in the degradation of prometryn, presumptively caused by the elevated concentration of inhibitory adjuvants, occurred. When pure prometryn was used, volumetric removal rates remarkably higher than those obtained with the herbicide formulation were estimated by fitting the raw experimental data to sigmoidal decay models, and differentiating them. When the microbial consortium was immobilized in a continuously operated biofilm reactor, the negative effect of adjuvants on the rate and removal efficiency of prometryn could not be detected. Using the herbicide formulation, the consortium showed volumetric removal rates greater than 20 g m(-3) h(-1), with prometryn removal efficiencies of 100 %. The predominant bacterial strains isolated from the microbial consortium were Microbacterium sp., Enterobacter sp., Acinetobacter sp., and Flavobacterium sp. Finally, by comparison of the prometryn removal rates with others reported in the literature, it can be concluded that the use of microbial consortia immobilized in a biofilm reactor operated in continuous regime offer better results than batch cultures of pure microbial strains.
采用分批培养法，通过连续传代驯化了能降解三嗪类除草剂的微生物群落。首先，采用游离细胞或附着在多孔载体碎片上的细胞来评估其降解普草津的能力。作为碳、氮和硫源，使用了普草津（纯度为 98.8%）或 Gesagard（一种含有 44.5%普草津和 65.5%助剂的除草剂制剂）。在分批培养中，由于助剂浓度较高，普草津的降解出现了明显的延迟。当使用纯普草津时，通过将原始实验数据拟合到指数衰减模型并进行微分，可以估计出比使用除草剂制剂更高的体积去除率。当微生物共混物固定在连续运行的生物膜反应器中时，助剂对普草津的去除率和去除效率的负面影响无法检测到。使用除草剂制剂，共混物显示出大于 20 g m(-3) h(-1)的体积去除率，普草津去除效率为 100%。从微生物共混物中分离出的主要细菌菌株为微杆菌属、肠杆菌属、不动杆菌属和黄杆菌属。最后，通过将普草津去除率与文献中报道的其他去除率进行比较，可以得出结论，使用固定在连续运行的生物膜反应器中的微生物共混物比纯微生物菌株的分批培养能提供更好的结果。
